// Filename: perlinNoise.I
// Created by:  drose (05Oct05)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) Carnegie Mellon University.  All rights reserved.
//
// All use of this software is subject to the terms of the revised BSD
// license.  You should have received a copy of this license along
// with this source code in a file named "LICENSE."
//
////////////////////////////////////////////////////////////////////


////////////////////////////////////////////////////////////////////
//     Function: PerlinNoise::fade
//       Access: Protected, Static
//  Description: Returns a smooth interpolation spline from 0 .. 1
//               for t.
////////////////////////////////////////////////////////////////////
INLINE double PerlinNoise::
fade(double t) { 
  //  return t * t * t * (t * (t * 6.0 - 15.0) + 10.0);
  return (3.0 - 2.0 * t) * t * t;
}

////////////////////////////////////////////////////////////////////
//     Function: PerlinNoise::lerp
//       Access: Protected, Static
//  Description: Returns the smoothly lerped value from a to b.
////////////////////////////////////////////////////////////////////
INLINE double PerlinNoise::
lerp(double t, double a, double b) { 
  return a + t * (b - a); 
}

////////////////////////////////////////////////////////////////////
//     Function: PerlinNoise::get_seed
//       Access: Published
//  Description: Returns a unique seed value based on the seed value
//               passed to this PerlinNoise object (and on its current
//               state).
////////////////////////////////////////////////////////////////////
INLINE unsigned long PerlinNoise::
get_seed() {
  return _randomizer.get_seed();
}